Noncircular cone loud-speaker



Dec. 31, 1929.

A. M- L. NICOLSON I v 1,741,533

. NONCIHCULAR CONE LOUD SPEAKER Filed March 11, 1927 2 Sheets-Sheet 1 INVENTOR ALEXANDER McLEAN NICOLSON TTORNEY D3131, 19291. I MCL. NICOLSON v 1,741,533

NONCIRCULAR CONE LOUD SPEAKER Filed March Il, 1927 I 2 Sheets-Sheet 2 INVENTOR. Y ALEXANDER McLEAN mcoLson w 5 W 'ATTQRNEY l noncircular periphery,preferably made up Patented Dec. 31, 1929 UNITED STATES PATENT OFFICE ALEXANDER IVICLEAN NICOESON, OF NEW YORK, N. Y., ASSIGNOR 'I O WIRED RADIO, INC., 015 NEW YORK N. Y., A CORPORATION OF DELAWARE 'NdNClIt-CULAR QONE LOUD-SPEAKER Application filed March 11, 1927. Serial No. 174,492.

This'invention relates to sound reproducung apparatusand more particularly to such apparatus comprising a relatively large direct acting diaphragm, that is, a diaphragm exposed on at least one side to unconfined air, and of sutiicient size to produce sound waves of the desired strength and quality, Without the use of baille plates and the like.

tions alone.

It is an obj ect of this invention to produce a sound reproducing diaphragm having a of a pair of elements formedas a mirror image of each other, and physically united in such manner that vibrations of the one react upon and affect the vibrations of the other, thereby providing a resultant mode-of vibration different from that of either of thefsec- Still other objects of this invention will be apparent from the specification.

The features of novelty which I loeli'eve to be characteristic of my invention are set forth with particularity in the appended claims. My invention itself, however, both as to. its fundamental principles and as to its practical applications, will best be understood'by ref erence to the specification and accompanying drawing, in which 1, 2 and 8 are respectively front and side elevations and top plan View of one form of apparatus according to my invention.

Figs. 4t and 5 are respectively a front elevation and top plan of a modified form of apparatus according to my invention.

Fig. 6 is a front elevation of a still further modified form of my invention. T In accordance with my invention, I pro vide a plurality of sound radiating dia phragm sections. In accordance withone aspect of this invention, the sections are incomplete; that is, mutilated circular cones, each having a similar section cut away or omitted, parallel to the vertical axis of the cone and spaced therefrom. The diaphragm sections are secured together alongthis intersection and means are provided for sup:

porting and" driving these sections, prefcomprises one or more piezo-electric crystals,

but it will be understood that other driving means may be substituted therefor, such for' example as an electro-magnetic unit, or the like.

. In accordance-with another aspect of my invention, instead of utilizing sections of cirs f cular conical diaphragms, I may usea pair of sections of elliptical conical-diaphragms.

which may be secured together as above described, forming a sound radiating member of substantially elliptical periphery. In this instance, the diaphragm may be formedwith what I term a ridge pole apex, in which the apex of the diaphragm instead of being'a single point as is usually the case, is in the form of a line extending across the diaphragm, and which,1s secured to the support ng and driving member.

In accordance with still another aspect of my invention, the diaphragm may be provided in the form of an elliptical cone, but instead ofapplying the driving force at a plurality of points on the diaphragm includin the focal points, the driving force is supplied to theapex which is in the form of a single point symmetrically disposed. with. ref-- erence tothe entire diaphragm. I

Referring now more particularly to Fig. 1, l designates a sound radiating diaphragm.

comprisin a pair of members 2 and 3, of

paper, cardboard, wood, composition or mctaheach in the form of a mutilated or incomplete circular cone, the cone 2 having an apex at and the cone 3 having an apex'5.

A section is omitted or cutfrom each of the cones along a line determined by passing a plane of intersection" through the diaphragm parallel tothe vertical axis, but laterally spaced therefrom, and the two sections are secured together at this line of intersection 6. The driving means for the diaphragm is preferably in the form of a piezoelectric crystal device 8 such as a crystal of Rochelle salt exhibiting the well known -honr glass configuration, provided with a pair of electrodes 9and 10, of any suitable form such for example as an internal electrode or an electrode at one or both basal planes, and an equatorial belt electrode of the crystal parallel to theb'asal plane.

Apair of stress plates 7 and 11 are also provided, suitably securedlto the crystal as by bolting or cementing bythe use'of Rochelle salt melt, formed by heating Rochelle salt at a temperatureabove itsmeltifig point to drive off the desired amount of Water. apexes 4 and 5 of the diaphragms' 2 and 3 are secured tothe ends of the stress plate 7 in any suitable manner as by cementing or bolting. The stress'plate 11 is secured as by p u tively large rlgld diaphragm comprising a bolting upon a relatively massive base 12.

It Will now be seen that if electrical oscil lations corresponding to sounds desired to be reproduced are impressed upon the electrodes 9 and 10, the crystal device 8 Will generate stresses or motions corresponding to the electrical oscillations and if the electrodes are in the form of an internal and external equatorial electrode forming a loop around the crystal, the stress plate 7 Will tend to oscillate upon the axis of the crystal, thereby impressing mechanical vibrations 180 out of phase upon the apexes 4 and 5 of the diaphragm sections 2 and 3. Each of these diaphragms Will be set into vibration bystress waves in the material travelling outwardly .from the apexes toward the peripheries and the reaction of these stress aves upon each other across the line of intersection 6 causes a modification of the mode ofvlbration of each of the .diaphragm sections from what would normally obtain, thereby causing a change in the quality of the sound.

Referring now more particularly to Figs.

4 and 5, in this instance, the diaphragm sec tions comprise elliptical sections 15 and 16 intersecting on the line of intersection 17. Instead of a single point apex, there may be provided what I term a ridge pole apex 18 of thesection 16', and a. similar apex 19 in the section 15, whereby the entire ridge pole apexes 18 and 19'may be secured-to the stress plate 7. It will be understood that if the line of intersection 17 passes through the exact center of each ofthe sections 15 and 16, the resultant diaphragm will be an ellipse. On the The parting sound vibrations to said diaphragms at the apexes thereof, said diaphragms merg- 9 ing one into the otherat the junction thereof.

5. A sound reproducer comprising a pair of substantially conical diaphragms positioned adjacent each other with their bases in the same vertical plane, a driver for imparting sound vibrations to said diaphragms at the apexes thereof, said d'iaphragms hav-- ing segments cut therefrom, said diaphragms being joined one with respect to the other substantially along'a chordal line through said diaphragms.

Signed at New York city in the county and State of New York this tenth day of March ALEXANDER McLEAN NICOLSON.

other hand, if the sectional line is displaced to one side or the other of the center of each of the sectional diaphragms, the periphery will vary from an ellipse.

Referring now more particularly to Fig. 6, in this instance I have shown an elliptical cone diaphragm formed in a single piece, and having a single apex 21 in the center thereof by which the diaphragm is secured to a suitable stress plate 22 mounted on the crystal 8.

It will be noted thatin the arrangement shown in Figs. 1 to 5 inclusive, the driving force is applied at a plurality of points on the diaphragm including the focal points, Whereas in the arrangement shown in Fig. 6, this is not the case.

While I have shown and described certain. i 

